Oberlechner Mg 23
The Mg 23 high performance single-seater was the last of the Mg series designed by Erwin Musger. Of conventional wood and fabric construction, the Mg 23 has cantilever single-spar shoulder wings with no flaps and wooden fabric-covered inset-hinge ailerons. Wooden Schempp-Hirth air brakes are fitted, and there are layers of plywood stiffening forward of the spar which, combined with a close rib spacing, make easier the production of a smooth polished wing surface. The semi-monocoque plywood fuselage is of oval section and the wooden tail unit has fabric covered rudder and elevators, and a Flettner-type tab in the starboard elevator. The landing gear consists of a non-retractable monowheel behind the eg, with a brake but with no shock absorber, plus a nose skid partly shock-absorbed by rubber, and a bow-shaped tailskid. The pilot sits under a jettisonable Plexiglas canopy which slides forward to open; the seat back and rudder pedals are adjustable and the cockpit is ventilated.
The MG-23 first flew on 25 June 1955. That was the year in which Austria had signed its State Treaty with the Allied occupying powers, and Soviet and Western troops withdrew from the country. With normal peacetime conditions returning for the first time since 1938, Austrian gliding amongst other activities began a resurgence and the Mg 23, as the Mg 19 had done before it, won the Austrian State Championships and set a number of new national records; it also equipped the country's national gliding team which began to re-establish Austria's prewar position in competition flying.
The Mg 23 was followed by the production Mg 23SL, which flew for the first time on 1 April 1962, and had a number of refinements including a longer, flush fitting cockpit canopy, larger fin and rudder and a lowered monowheel. It is cleared for cloud flying and spinning, but is not acrobatic; it was awarded type approval by the US FAA, as well as by the Austrian authorities, and examples have been exported to the USA and Canada.
and was followed down the production line by the improved 1963 MG-23SL with taller fin, longer canopy and lowered main wheel.
Approximately 90 were built when production ceased in 1967.
Mg 23 SL
Wing span: 16.4 m / 53 ft 9.5 in
Wing area: 14.21 sq.m / 153 sq.ft
Length: 23 ft 4 in
Height: 4 ft 10.75 in
Empty Weight: 240 kg / 530 lb
Payload: 120 kg / 263 lb
Gross Weight: 360 kg / 793 lb
Max speed: 137 mph (in smooth air)
Max aero-tow speed: 80 mph
Wing Load: 25.33 kg/sq.m / 5.2 lb/sq.ft
L/DMax: 33 85 kph / 46 kt / 53 mph
MinSink: 0.64 m/s / 2.1 fps / 1.24 kt at 48.5 mph
Aspect ratio: 18.54
Airfoil: NACA 63-315